Previously, Blue Lake, situated in Bau Minor District appears as a well known gold mine in Sarawak. This lake of 5 hectares is thousands of metres deep. At one instance, a foreign company drained out Blue Lake again to excavate the gold. During that time, the locals saw how small a 10-ton lorry was at the bottom of it. It looks like a matchbox. Perhaps many did not know the lake contains gold, which was the most beautiful in the world and of quality. At one occasion, there were sediments at various places in Bau including the old site of Bau National Secondary School (BNSS) due to the renewed mining activities in the lake. Resulting from that sediment, the locals became annoyed and objected to the renewed mining. After the locals' objections, finally in 1998, the lake was refilled with water and the mining officially ceased. Following that, the sediments stopped immediately. Now Blue Lake has become one of the eco-tourism attractions in this state. It opened its door to the public who wish to exercise whilst enjoying the fresh air. Additionally visitors could see for themselves the shape and blue colour of the man made lake and ponder upon its history hidden in it.